A federal agent is the subject of an internal investigation after an early morning traffic stop and arrest by an Arkansas State Police trooper who reported finding a beer inside the agent's government-owned sport utility vehicle.

Grover Crossland, the head agent of Little Rock's Bureau of Alcohol, Tobacco, Firearms and Explosives field office, confirmed Friday that ATF agent John Norris was arrested July 25 in Sherwood and that per policy, internal investigators in the agency's Washington, D.C., headquarters are conducting a review of Norris' conduct.

Norris, 37, was charged with driving while intoxicated, as well as refusing to submit to alcohol testing, driving with a defective taillight and driving the wrong way on a one-way road.

When asked whether Norris returned to work this week after his arrest or whether he had been placed on administrative leave, Crossland declined to comment on the agent's work status.

A phone number for Norris was not found.

According to arrest records, a state trooper went to the area of U.S. 67 and Wildwood Avenue in Sherwood after a "concerned citizen" reported a driver's odd maneuvers and overall appearance.

When the trooper caught up with the vehicle about 1 a.m., the 2008 Jeep Cherokee was going the wrong way on a one-way road.

During the traffic stop, Norris turned on his own sirens, which were included in the federal vehicle, according to a police report.

The trooper noticed that the vehicle's tags were expired and that its taillights were defective, adding that Norris "had all the signs of impairment," according to the report.

After finding a beer inside the vehicle, the trooper had Norris perform several field sobriety tests, and he "exhibited several clues" of impaired driving.

According to the report, the federal agent refused a blood-alcohol test and was placed under arrest.

When interviewed Friday, Crossland declined to say how long Norris has worked with the federal law enforcement agency or what role he played, other than being "an agent."

Crossland declined to comment on Norris' past disciplinary history, including whether Norris had any other run-ins with law enforcement agencies in the past.

"He'll have to go through the whole judicial process just like any other person," Crossland said. "Administratively, our [internal affairs] division in [Washington] will investigate it, and whatever appropriate discipline action [they find], they'll do."

Citing an ongoing investigation, state police declined to release audio or video from Norris' stop and arrest.